Musical pen with small central button



FIG. 1 is a perspective illustration embodying my new design;

FIG. 2 is a top plan view;

FIG. 3 is a front plan view;

FIG. 4 is a left side plan view;

FIG. 5 is a rear plan view; and,

FIG. 6 is a bottom plan view; 

The ornamental design for a musical pen with small central button, as shown. 